The invention relates to a means for production of electrical contacts for electrically joining at least one electrical valve drive to a printed circuit board, comprising first contact elements for the production of electrical connections between a connection part of the valve drive and second contact elements arranged on the printed circuit board. Furthermore, the invention relates to a valve arrangement having at least one valve which is provided with at least one electrical valve drive which is electrically connected by means of first contact elements provided on a connection part with second contact elements provided on a printed circuit board.
The German patent publication 4,222,637 C2 discloses a valve arrangement, in the case of which a plurality of valves are mounted on a fluid manifold and are fitted respectively with one or more electrical valve drives. For the operation of the valves the valve drives are driven by actuating signals, which are supplied by way of a printed circuit board. In order to produce an electrical contact between the valve drives and the printed circuit board L-shaped connection parts are provided electrically connected with the valve drives, such connection parts being provided with pin-like contact elements fitting into sleeve-like contact elements on the printed circuit board.
A similar arrangement is disclosed in the German patent publication 3,910,913 A1. This differs from the arrangement of the said German patent publication 4,222,637 C2 as regards electrically contacting the valve drives, essentially, merely in as far as the connection part bearing the pin-like contact elements is not designed separately but as an integral component of the valve drive.
The contact producing means employed in known valve arrangements are extremely reliable and in the case of average valve dimensions are able to be produced without substantial tolerance problems. However, such a contact making technology meets its limits in the case of valve arrangements or valve drives with small and miniature dimensions. If at all in this case it is only possible to produce an exactly fitting electrical connection between the contact elements of the valve drives and the contact elements of the printed circuit board if an extremely exacting manufacturing process is employed.
One object of the invention is to produce a contacting means and a valve arrangement of the type initially mentioned, which renders possible a precise and reliable contact on the valve drives in the case of small and miniature dimensions involving only a fair amount of manufacturing complexity.
In order to achieve these and/or other objects appearing from the present specification, claims and drawings, in the present invention in the case of a contacting means of the type initially mentioned there is a support housing to be arranged between the connection part and the printed circuit board, such housing having a contacting unit, which is arranged for the respective electrical connection to be produced in a through duct, and is resiliently elastic in the longitudinal direction of the duct, such contacting unit being adapted, when the valve drive is contacted, to be acted on at one end by a contact face of a first contact element and at the other end by a contact face of a second contact element of the printed circuit board, and owing to the resulting compression to touch the two contact faces with a resilient spring bias.
Furthermore, the object of the invention is to be attained in the case of valve arrangement of the type initially mentioned by a contacting unit, which comprises a support housing arranged between the connection part and the printed circuit board, such housing having, for the respective electrical connection to be produced, a contacting unit arranged in a through duct and being resiliently elastic in the longitudinal direction of the duct, such contacting unit being acted upon at one end by a contact face of a first contact element of the connection part and at the other end by a contact face of a second contact element of the printed circuit board, and which owing to compression resulting from being acted upon touches the two contact faces with a resilient bias.
In the case of this contacting technology a support housing is placed between the connection part of the valve drive to be electrically contacted and the printed circuit board, such support housing being provided with through ducts in which the resilient elastic contacting units are located. The contacting units are of such a size that when the valve drive is installed they are compressed between a first contact element of the connection part of the valve drive and a second contact element of the printed circuit board and owing to the resulting spring bias are braced between the contact faces on each side or end. Accordingly there will be a reliable electrical connection with an automatic compensation of manufacturing inaccuracies. Furthermore, in a very small overall space, the resilient elasticity of the contact units means that a large contact distance between the contact elements may be spanned in an adjustable manner. The deformation of the spring and the spring force may be changed practically to any desired extent and designed in accordance with the particular case of application. Since the direct contact making action does not need any plug connection and a simple touching action is sufficient, not only manufacturing inaccuracies in the longitudinal of the through ducts but also those athwart the longitudinal direction may be compensated. By means of the support housing the contacting means are reliably guided and held in place. The means renders possible use without specially adapted and complex contacting means having to be provided on the valve drives or on the printed circuit board.
The German patent publication 19,706,636 C2 does admittedly disclose valve drives using stamped spring contact elements for making contact with an electronic control simply by touching and without plug means. However this design requires special customized comb-like connecting members, whose manufacture is relatively costly.
Further advantageous developments of the invention are defined in the claims.
As a rule electrical valve drives, as for example solenoid valve drives, possess at least two normally pin-like contact elements. Accordingly in the support housing it is convenient for a corresponding number of through ducts and contacting units to be provided for each valve drive to be contacted.
The contacting means is suitable both for contacting only one valve drive and also for the simultaneous contacting of a plurality of valve drives. It is particularly in the latter case that instead of a single-part support housing a design may be suitable, in the case of which the support housing possesses a plurality of support housing segments.
The support housing may be a component of a hood-like support body, which may accommodate the printed circuit board to be connected. The support housing may in this case constitute the top wall section of the hood-like support body.
It is an advantage for the through duct or ducts of the support housing to have abutment means arranged in them, which prevent, the removal of the contacting units contained therein, at least toward the valve drive side. This means that there is an accommodation of the contacting units without risk of loss, even when the valve drive is not fitted. The insertion of the contacting units in the through ducts is preferably implemented before the installation of the printed circuit board through the openings, which face the printed circuit board, of the through ducts. These openings accordingly constitute assembly openings.
The abutment means may constitute a sealing seat, against the associated contacting unit rests, loaded by spring means, when the valve drive is not contacted. This means that when the valve drive is dismounted no dirt may find its way to the contact area.
In a preferred design the contacting units respectively comprise a compression spring, which at one end may bear against one of the contact faces of the printed circuit board and on which at the other end a contacting body is arranged which is able to be moved in relation to the through duct, which body is adapted for being acted upon by a first contact element of the valve drive to be electrically contacted. The compression spring in this case preferably directly constitutes an electrical conductor, which transmits the electrical signals within the contacting unit. There may be a provision such that the compression spring directly touches the associated contact face of the printed circuit board so that owing to such touching contact the desired electrical contacting action is provided between the contacting unit and the printed circuit board. As an alternative it is however possible to have a merely indirect mechanical contact on the contact face of the printed circuit board, more particularly by the use of a contacting body, placed in front of the compression spring, and similar to that one employed for contacting the contact elements provided on the connection part.
Preferably the arrangement is such that the contacting body, when the valve drive is not installed, is moved into a home position by the compression spring. The compression spring may in this case, but does not necessarily have to, be subject to a biasing resilient force. On fitting the valve drive the contacting body is acted upon by the first contact element and shifted toward the printed circuit board so that the length of the contacting unit is reduced and simultaneously a return force is built up, by which the contacting unit is spring loaded between the contact faces of the two contact elements.
A particularly reliable function may be ensured if the contacting body is spherical in form. This prevents skew positioning on being moved within the associated through duct.
As a compression spring element, as for example a helical spring, or however a plurality of combined spring elements, as for instance a stack of belleville washers, may be utilized.
In order, during operation with a valve arrangement fitted with the contacting means, to avoid ingress of moisture into the contact making area, it is an advantage for the support housing to possess a socket on the valve drive side (facing the at least one valve drive) adjacent to the openings of the through ducts, such socket serving to receive a seal to be placed between the support housing and the connection part.
Further advantageous developments and convenient forms of the invention will be understood from the following detailed descriptive disclosure of one embodiment thereof in conjunction with the accompanying drawings.